Special vehicle display screen anti-flash protection circuit and power management system

Abstract

The utility model provides a special vehicle display screen anti-screen flash protection circuit and a power management system, the special vehicle display screen anti-screen flash protection circuit comprises a microcontroller module and an enabling protection module, and the enabling protection module is composed of a signal control switch tube and an isolation diode. The anode of the isolating diode is connected with the display screen enable signal output end of the microcontroller, and the cathode is connected with the control end of the switching tube; the first end of the switch tube is connected with a vehicle-mounted display screen driving signal output end, and the second end is grounded. When a special vehicle is ignited and started, the circuit forcibly pulls down a display screen driving signal to a low level through the switching tube, so that the display screen enters a transient closing state, and power supply is recovered after a power supply system is stable, thereby avoiding the impact of voltage transient on a display module, preventing the vehicle-mounted display screen from flickering, and prolonging the service life of the display screen. And the running stability and durability of the display screen of the special vehicle are further improved.

Description

Technical Field

[0001] This disclosure relates to the technical field of power management for special vehicles, and in particular to a screen flicker protection circuit and power management system for a special vehicle display screen. Background Technology

[0002] In practical applications of special vehicles (such as fire trucks, ambulances, and police cars), their onboard power systems are prone to significant voltage fluctuations during startup because these vehicles often need to respond quickly in emergency situations. This is mainly due to the instantaneous high current demand during engine startup, the simultaneous startup of external high-power equipment, and voltage fluctuations caused by the inductive effect in the power supply lines.

[0003] However, in the existing technology, the enable signal of the vehicle display screen of special vehicles is directly controlled by the power supply status. When the special vehicle starts, voltage fluctuations can easily cause the enable signal to increase abnormally. When this happens, the control chip inside the display screen may malfunction because the input voltage exceeds the design threshold, causing screen flickering, screen distortion, or even a brief black screen. This accelerates the aging of components such as the display screen backlight module and driver chip, thereby shortening the overall service life of the vehicle display screen. Utility Model Content

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a special vehicle display screen anti-flicker protection circuit and power management system that effectively extends the overall service life of the vehicle display screen.

[0005] The purpose of this disclosure is achieved through the following technical solution:

[0006] A special vehicle display screen anti-flicker protection circuit includes a microcontroller module and an enable protection module. The enable protection module includes a signal control switch and an isolation diode. The positive terminal of the isolation diode is connected to the display screen enable signal output terminal of the microcontroller module, and the negative terminal of the isolation diode is connected to the control terminal of the signal control switch. The first terminal of the signal control switch is used to connect to the drive signal output terminal of the vehicle display screen, and the second terminal of the signal control switch is grounded.

[0007] In one embodiment, the enable protection module further includes a voltage regulator filter unit, the input terminal of which is connected to the display screen enable signal output terminal, and the output terminal of which is connected to the positive terminal of the isolation diode.

[0008] In one embodiment, the voltage stabilizing filter unit includes a first filter capacitor and a filter resistor. The first end of the first filter capacitor and the first end of the filter resistor are both connected to the display screen enable signal output terminal, and the second end of the first filter capacitor and the second end of the filter resistor are both connected to the ground terminal.

[0009] In one embodiment, the voltage regulation and filtering unit further includes a voltage suppression diode, one end of which is connected to the display screen enable signal output terminal, and the other end of which is connected to the ground terminal.

[0010] In one embodiment, the enable protection module further includes a current-limiting resistor, the first end of which is connected to the negative terminal of the isolation diode, and the second end of which is connected to the control terminal of the signal control switch.

[0011] In one embodiment, the enable protection module further includes a bias resistor, the first end of which is connected to the control terminal of the signal control switch transistor, and the second end of which is connected to the second terminal of the signal control switch transistor.

[0012] In one embodiment, the enable protection module further includes a voltage divider resistor, the first end of which is connected to the drive signal output terminal of the vehicle display screen, and the second end of which is connected to the first end of the signal control switch transistor.

[0013] In one embodiment, the microcontroller module includes a main control chip and a second filter capacitor. The display enable signal output terminal of the main control chip is connected to the positive terminal of the isolation diode. One end of the second filter capacitor is used to connect to the external power supply terminal, and the other end of the second filter capacitor is grounded.

[0014] In one embodiment, the signal control switch is an NPN transistor.

[0015] This application provides a power management system, including the anti-flicker protection circuit for a special vehicle display screen as described in any embodiment.

[0016] Compared with the prior art, this disclosure has at least the following advantages:

[0017] The aforementioned anti-flicker protection circuit for special vehicle displays pulls the drive signal of the vehicle display to a low level through a signal control switch tube at the moment the special vehicle starts, so that the vehicle display is temporarily turned off and restarted after the power supply is normal. This effectively protects the display from the influence of abnormal enable signals and prevents the vehicle display from flickering, thereby extending the overall service life of the vehicle display. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a circuit diagram of a special vehicle display screen anti-flicker protection circuit according to one embodiment. Detailed Implementation

[0020] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0021] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0024] like Figure 1 As shown, a special vehicle display screen anti-flicker protection circuit 10 according to an embodiment of the present disclosure includes a microcontroller module 100 and an enable protection module 200. The enable protection module 200 includes a signal control switch Q1 and an isolation diode D2. The positive terminal of the isolation diode D2 is connected to the display screen enable signal output terminal BL-EN of the microcontroller module 100, and the negative terminal of the isolation diode D2 is connected to the control terminal of the signal control switch Q1. The first terminal of the signal control switch Q1 is used to connect to the drive signal output terminal CAM_EN of the vehicle display screen, and the second terminal of the signal control switch Q1 is grounded.

[0025] In this embodiment, when the special vehicle power supply system starts, the sudden increase in current in the circuit may cause instantaneous voltage fluctuations. These voltage transients may exceed the normal operating range, resulting in abnormal signals. Therefore, to prevent abnormal signals from being generated by the vehicle power system when it starts, the microcontroller module 100 outputs an enable signal from its display enable signal output terminal BL-EN to the isolation diode D2. The isolation diode D2 transmits the enable signal to the control terminal of the signal control switch Q1, causing the voltage at the control terminal of the signal control switch Q1 to rise. At this time, the voltage at the control terminal is greater than the conduction threshold voltage of the signal control switch Q1, causing the signal control switch Q1 to conduct. Since a path is formed between the first and second terminals of the signal control switch Q1, and the second terminal is grounded, the conduction of the signal control switch Q1 is equivalent to grounding the drive signal output terminal CAM_EN of the vehicle display connected to the first terminal through the signal control switch Q1. This pulls the drive signal of the vehicle display to a low level, thereby avoiding the problem of the display malfunctioning due to abnormal voltage fluctuations that easily occur when the special vehicle starts.

[0026] The aforementioned anti-flicker protection circuit 10 for special vehicle displays pulls the drive signal of the vehicle display to a low level through the signal control switch Q1 at the moment the special vehicle starts, so that the vehicle display is temporarily turned off and restarted after the power supply is normal. This effectively protects the display from the influence of abnormal enable signal and prevents the vehicle display from flickering, thereby extending the overall service life of the vehicle display.

[0027] like Figure 1 As shown, in one embodiment, the enable protection module 200 further includes a voltage regulator and filter unit. The input terminal of the voltage regulator and filter unit is connected to the display enable signal output terminal BL-EN, and the output terminal of the voltage regulator and filter unit is connected to the positive terminal of the isolation diode D2. In this embodiment, when the vehicle power supply system is started, the display enable signal may generate high-frequency noise due to power fluctuations. At this time, the voltage regulator and filter unit can absorb the high-frequency noise and smooth the voltage waveform through the charging and discharging characteristics of the internal components. At the same time, it suppresses current surges and filters out high-frequency noise. The enable signal after voltage regulation and filtering is transmitted to the positive terminal of the isolation diode D2, so that when the isolation diode D2 is forward-biased, it transmits the regulated enable signal to the control terminal of the signal control switch Q1, thereby driving it to conduct.

[0028] like Figure 1As shown, in one embodiment, the voltage stabilizing filter unit includes a first filter capacitor C1 and a filter resistor R1. The first terminals of both the first filter capacitor C1 and the filter resistor R1 are connected to the display enable signal output terminal BL-EN, and the second terminals of both are connected to the ground terminal. In this embodiment, when the vehicle power supply system starts and the display enable signal output terminal BL-EN generates high-frequency noise or transient voltage spikes, the high-frequency noise is significantly attenuated as it passes through the filter resistor R1 because of its significant impedance to high-frequency signals. Simultaneously, the filter resistor R1 and the first filter capacitor C1 together form a low-pass filter. The first filter capacitor C1 functions as both an energy storage and filter in the circuit, smoothing voltage fluctuations. When a transient voltage change occurs, the first filter capacitor C1 charges or discharges rapidly to maintain relative stability of its voltage. The filter resistor R1 limits the charging and discharging current of the capacitor, making the charging and discharging process smoother and further improving the filtering effect.

[0029] like Figure 1 As shown, in one embodiment, the voltage regulation and filtering unit further includes a voltage suppression diode D1. One end of the voltage suppression diode D1 is connected to the display enable signal output terminal BL-EN, and the other end is connected to the ground terminal. In this embodiment, when the display enable signal voltage is normal, the voltage suppression diode D1 is in a reverse bias state. At this time, the voltage suppression diode D1 is equivalent to an open switch, having almost no impact on the normal signal, and the signal can pass smoothly and be transmitted to subsequent circuits. However, when a voltage transient overshoot occurs at the moment the power supply system starts up, and the enable signal voltage rises to exceed the reverse breakdown voltage of the voltage suppression diode D1, the voltage suppression diode D1 will break down and conduct, thereby providing a low-impedance discharge path for the excessively high voltage, quickly releasing the excess charge to the ground terminal, and thus effectively preventing the excessively high voltage from damaging subsequent circuits.

[0030] like Figure 1As shown, in one embodiment, the enable protection module 200 further includes a current-limiting resistor R2. The first end of the current-limiting resistor R2 is connected to the negative terminal of the isolation diode D2, and the second end of the current-limiting resistor R2 is connected to the control terminal of the signal control switch Q1. In this embodiment, at the moment the special vehicle power supply system is started, the microcontroller module 100 outputs an enable signal, which is transmitted to the current-limiting resistor R2 via the isolation diode D2. Since the current-limiting resistor R2 is connected in series between the control terminal of the signal control switch Q1 and the negative terminal of the isolation diode D2, according to Ohm's law, if the enable signal voltage increases instantaneously, the voltage drop across the current-limiting resistor R2 will also increase accordingly. This allows the current-limiting resistor R2 to limit the current flowing to the control terminal of the signal control switch Q1, thus preventing excessive current from damaging the signal control switch Q1.

[0031] like Figure 1 As shown, in one embodiment, the enable protection module 200 further includes a bias resistor R4. The first end of the bias resistor R4 is connected to the control terminal of the signal control switch Q1, and the second end of the bias resistor R4 is connected to the second terminal of the signal control switch Q1. In this embodiment, when the microcontroller module 100 outputs an enable signal, the enable signal passes through the voltage regulator filter unit, the isolation diode D2, and the current-limiting resistor R2 before reaching the control terminal of the signal control switch Q1. At this time, according to Ohm's law, the control terminal voltage is shared by the enable signal voltage, the voltage drop across the current-limiting resistor R2, and the bias resistor R4. This allows the bias resistor R4 to slow down the rise rate of the control terminal voltage during the rising edge of the enable signal through voltage division, preventing instantaneous overcurrent in the signal control switch Q1 due to voltage fluctuations. Furthermore, when the microcontroller module 100 does not output an enable signal, the control terminal of the signal control switch Q1 is directly grounded through the bias resistor R4, and the resistance value of the bias resistor R4 is sufficiently large. At this time, the bias resistor R4 provides a low-level bias to the control terminal, ensuring that the switching transistor is in a reliable off state, thereby avoiding the switching transistor from being mis-turned on due to electromagnetic interference or residual voltage, and thus preventing the vehicle display screen from being accidentally turned off during non-start-up phases.

[0032] like Figure 1As shown, in one embodiment, the enable protection module 200 further includes a voltage divider resistor R3. The first end of the voltage divider resistor R3 is connected to the drive signal output terminal CAM_EN of the vehicle display screen, and the second end of the voltage divider resistor R3 is connected to the first end of the signal control switch Q1. In this embodiment, when the microcontroller module 100 outputs an enable signal to turn on the signal control switch Q1, the voltage divider resistor R3 and the turned-on signal control switch Q1 form an approximately low-resistance path, and a loop is formed between the vehicle display screen drive signal output terminal and the ground terminal. At this time, the display screen drive signal is transmitted to the signal control switch Q1 through the voltage divider resistor R3, so that during the switch's conduction process, the voltage divider resistor R3 can buffer changes in the drive signal, thereby preventing the drive signal from being directly applied to the signal control switch Q1 and causing damage.

[0033] like Figure 1 As shown, in one embodiment, the microcontroller module 100 includes a main control chip U1 and a second filter capacitor C2. The display enable signal output terminal BL-EN of the main control chip U1 is connected to the positive terminal of the isolation diode D2. One end of the second filter capacitor C2 is connected to the external power supply terminal, and the other end of the second filter capacitor C2 is grounded. In this embodiment, the main control chip U1 is model N32G435CBL7. The main control chip U1 can accurately control the output of the enable signal to ensure that an effective enable signal is output in time at the moment the power supply system starts up, and triggers the action of the enable protection module 200, thereby effectively avoiding damage to the vehicle display screen due to abnormal voltage at the moment of startup. When the external power supply is normal, the DC voltage provided by the power supply is applied to the two ends of the second filter capacitor C2, so that a voltage difference gradually forms between its two ends. As the charging time increases, the charge accumulated at the two ends of the second filter capacitor C2 gradually increases, and the voltage across the capacitor gradually increases until it approaches the power supply voltage. When the external power supply fluctuates or is interrupted momentarily, the second filter capacitor C2 begins to discharge. The capacitor provides a stable power supply to the microcontroller module 100 through its internal charge storage, so as to maintain the normal operating voltage of the microcontroller module 100.

[0034] like Figure 1As shown, in one embodiment, the signal control switch Q1 is an NPN transistor. In this embodiment, the first terminal of the signal control switch Q1 is the collector of the NPN transistor, the second terminal of the signal control switch Q1 is the emitter of the NPN transistor, and the control terminal of the signal control switch Q1 is the base of the NPN transistor. When the microcontroller module 100 does not output an enable signal, the isolation diode D2 is in a reverse bias state. Therefore, the gate voltage (i.e., the control terminal) of the signal control switch Q1 is close to 0V and grounded through the bias resistor R4, so that the driving signal of the vehicle display screen is effectively isolated. When the microcontroller module 100 outputs an enable signal, the enable signal is transmitted to the gate of the signal control switch Q1 through the voltage regulator filter unit and the isolation diode D2, causing the gate voltage to rise and exceed the threshold voltage. The signal control switch Q1 is turned on, so that a low-impedance path is formed between its drain and source. At this time, the drive signal output terminal CAM_EN of the vehicle display screen is connected to the ground terminal through the on-state signal control switch Q1. The drive signal is pulled to a low level, and the vehicle display screen is temporarily turned off to prevent damage to the display screen due to abnormal voltage fluctuations. On the other hand, after the power supply is normal, the microcontroller module 100 can adjust the output of the enable signal as needed to control the on and off state of the control switch Q1, thereby realizing the on and off control of the vehicle display screen.

[0035] This application provides a power management system, including a special vehicle display screen anti-flicker protection circuit 10 according to any embodiment. In this embodiment, when the special vehicle power supply system starts, the sudden increase in current in the circuit may cause instantaneous voltage fluctuations. These voltage transients may exceed the normal operating range, thereby generating abnormal signals. Therefore, when the special vehicle power supply system starts, to avoid abnormal signals from the vehicle power system, the display screen enable signal output terminal BL-EN of the microcontroller module 100 outputs an enable signal to the isolation diode D2. The isolation diode D2 transmits the enable signal to the control terminal of the signal control switch Q1, causing the control terminal voltage of the signal control switch Q1 to rise. At this time, the control terminal voltage is greater than the conduction threshold voltage of the signal control switch Q1, causing the signal control switch Q1 to conduct. Since a path is formed between the first and second terminals of the signal control switch Q1, and the second terminal is grounded, when the signal control switch Q1 is turned on, it is equivalent to grounding the drive signal output terminal CAM_EN of the vehicle display screen connected to the first terminal through the signal control switch Q1. This pulls the drive signal of the vehicle display screen to a low level, thereby avoiding the problem that the display screen cannot work properly due to abnormal voltage fluctuations that are prone to occur at the moment of starting special vehicles.

[0036] Compared with the prior art, this disclosure has at least the following advantages:

[0037] The aforementioned anti-flicker protection circuit 10 for special vehicle displays pulls the drive signal of the vehicle display to a low level through the signal control switch Q1 at the moment the special vehicle starts, so that the vehicle display is temporarily turned off and restarted after the power supply is normal. This effectively protects the display from the influence of abnormal enable signal and prevents the vehicle display from flickering, thereby extending the overall service life of the vehicle display.

[0038] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A special vehicle display screen anti-screen flicker protection circuit, characterized in that, Includes a microcontroller module and an enable / protection module. The enable protection module includes a signal control switch and an isolation diode. The positive terminal of the isolation diode is connected to the display enable signal output terminal of the microcontroller module, and the negative terminal of the isolation diode is connected to the control terminal of the signal control switch. The first terminal of the signal control switch is used to connect to the drive signal output terminal of the vehicle display, and the second terminal of the signal control switch is grounded.

2. The special service vehicle display screen anti-screen flicker protection circuit of claim 1, wherein, The enable protection module also includes a voltage regulator filter unit. The input terminal of the voltage regulator filter unit is connected to the enable signal output terminal of the display screen, and the output terminal of the voltage regulator filter unit is connected to the positive terminal of the isolation diode.

3. The anti-flicker protection circuit for special vehicle displays according to claim 2, characterized in that, The voltage stabilizing filter unit includes a first filter capacitor and a filter resistor. The first end of the first filter capacitor and the first end of the filter resistor are both connected to the enable signal output terminal of the display screen, and the second end of the first filter capacitor and the second end of the filter resistor are both connected to the ground terminal.

4. The special service vehicle display screen anti-screen flicker protection circuit of claim 2, wherein, The voltage regulation and filtering unit also includes a voltage suppression diode, one end of which is connected to the enable signal output terminal of the display screen, and the other end of which is connected to the ground terminal.

5. The anti-flicker protection circuit for special vehicle displays according to claim 1, characterized in that, The enable protection module also includes a current-limiting resistor, the first end of which is connected to the negative terminal of the isolation diode, and the second end of which is connected to the control terminal of the signal control switch.

6. The special service vehicle display screen anti-screen flicker protection circuit of claim 5, wherein, The enable protection module further includes a bias resistor, the first end of which is connected to the control terminal of the signal control switch transistor, and the second end of which is connected to the second terminal of the signal control switch transistor.

7. The special service vehicle display screen anti-screen flicker protection circuit of claim 5, wherein, The enable protection module also includes a voltage divider resistor, the first end of which is connected to the drive signal output terminal of the vehicle display screen, and the second end of which is connected to the first end of the signal control switch.

8. The special service vehicle display screen anti-screen flicker protection circuit of claim 1, wherein, The microcontroller module includes a main control chip and a second filter capacitor. The display enable signal output terminal of the main control chip is connected to the positive terminal of the isolation diode. One end of the second filter capacitor is used to connect to the external power supply terminal, and the other end of the second filter capacitor is grounded.

9. The special service vehicle display screen anti-screen flicker protection circuit of claim 1 wherein, The signal control switch is an NPN transistor.

10. A power management system, characterized by, Includes the anti-flicker protection circuit for special vehicle displays as described in any one of claims 1 to 9.

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